Using large mammal communities to examine ecological and taxonomic structure and predict vegetation in extant and extinct assemblages

Abstract

Evolutionary paleoecology is the study of paleoecological patterns of organization over time. However, identification of such patterns within modern communities must be made before any study over time can be attempted. This research analyzes mammalian ecological diversity of 31 African localities classified into eight vegetation types: forests, closed woodlands, closed woodland/bushland transition, bushlands, open woodlands, shrublands, grasslands, and deserts. Ecological diversity is measured as the relative proportions of large mammal trophic and locomotor behaviors within communities. Trophic and locomotor adaptations are assigned on the basis of published observations and stomach contents of 184 African mammal species. Communities are accordingly described on the basis of total percentages of mammalian trophic and locomotor adaptations. Since many paleoecology studies have been made using taxonomic uniformitarianism, this study also examines taxonomic community structure to compare with ecologically derived patterns. Results indicate that particular types of vegetation have predictable percentages of arboreal, aquatic, frugivorous, grazing, etc. large mammals. Therefore, these adaptations, because they are predictable in extant assemblages, can be used to predict paleovegetation as well as to portray the community structure of fossil assemblages. Taxonomic groupings also can be used to predict vegetation in extant assemblages, and taxonomic patterns in communities are compared with ecological ones. The mammalian communities of the Pliocene fossil locality Makapansgat, South Africa, are interpreted using these ecological and taxonomic methodologies. Trophic and locomotor adaptations are assigned for Makapansgat fossil mammals through morphological examination of each taxon. Vegetation type is predicted for these fossil localities, but ecological and taxonomic differences in the assemblages differ from extant communities.